Southern Magnolia (Magnolia grandiflora}
Southern magnolia is a large tree, growing to 60 to 80 feet in height with a spread of about 30 to 50 feet. Its mature trunk diameter is usually over 3 feet. The more majestic trees can attain heights of 90 or 100 feet. This tree has a medium growth rate with a pyramidal habit. Generally it has branches right down to the ground. Those branches are best left that way since growing anything under them is usually futile because of the tree’s dense, shallow root system. Trees planted in full sun should have their lower limbs left in place to reduce soil moisture loss.
The only evergreen magnolia, the Southern Magnolia has alternate leaves with dark glossy green on the top sides, with a fuzzy looking rusty or light brown color underneath. The leaves feel very thick and stiff; almost leathery in texture. The foliage can vary from 5” to 10” in length, 4” to 5” in width.
It is not unusual for Southern magnolias to drop a bunch of leaves in June, scaring the new homeowner unaware of such behavior. Actually most trees will shed some leaves all season long. The old leaves are steadily replaced by new leaves. The old leaves that accumulate under the tree seem to take forever to decompose, viewed as a problem by many homeowners. An excellent ground cover designed to catch the leaves and hide them from view while they decompose is the grassy Liriope, either the green or variegated version. With such tough texture its not surprising that leaf-eating insects seldom damage this tree.
Magnolias bear the largest flowers of any cultivated tree. In late spring showy creamy white flowers with a sweet lemony fragrance take over the tree. These plate sized blooms can be 5” to 12” in diameter. The blossoms vary in the number of petals (9-15) and last only for two to four days. On the first day they are cup-shaped, after that they become saucer-shaped. Flowering begins in late May-early June and continues sporadically throughout the summer. The flower buds are protected by attractive downy pods that decorate the magnolia branches over the winter months.
The fruit is a pinkish red aggregate of follicles about 5” in length, splitting open in the late summer to expose dark red seeds, loved by wildlife. When the seeds ripen, they are expelled from the fruit, but are held for a few days by short silky strands before falling to the ground. This tree is a show-off even when it’s dropping its seeds.
Southern Magnolia Choices
There are more than 100 cultivars listed for this tree.
Edith Bogue is conical and more cold hardy than most, with creamy white flowers that bloom in June and July.
'Little Gem' is a dwarf Southern Magnolia with smaller dark green foliage and very compact narrow form ideal for smaller gardens. The leaves of this evergreen shrub or small tree are rusty-brown on the undersides. A heavy bloomer, white flowers appear early and again late in summer. Evergreen, Full sun, Moderate growing to 20 to 25 feet high and 10 to 15 feet wide. Zones 3 to 9. Grown by Monrovia.
Bracken's Brown Beauty is an elegant, compact and dense flowering tree producing lustrous, leathery foliage that is rich, dark green above and cinnamon brown underneath with an undulating surface. Large, 5 to 6 inch creamy white flowers make their appearance in late spring and are exotically fragrant. They are followed by 3 to 3 inch long fruits. Transplants well and does not lose as many leaves as other varieties. Full sun to partial shade, Evergreen. Reaches matruity at 30 to 50 feet and 15 to 30 feet wide. AHS Zones 3 - 9. Grown by Monrovia.
St. Mary has a compact form with white flowers and glossy dark green leaves. It is ranked as the best in the South.
Harold Poole, H.D. Blackwell and Samuel Sommer with flowers 14 inches across are also good selections for the South.